overstayed my visa in japan - help!

this is my story in japan :so i camed to japan in april 2012 i had some problems in my home country that i cant explain (sorry) .. and bcz of thoes problems i was not planing to go back my girlfriend lives here so we was thinking to get married and just start a new life toghether ... when i came to japan they gived me a 90 days tourist visa i start living with my girlfriend and evry thing was ok ... then when we started preparing for the wedding we found out that my gf have some problems with her papers so to avoide overstaying i went to corea for 1 week and came back but later they told us that my gf papers will take time to be fixed so i went back to corea again bfr the second 90 days are over just for 1 day when i went back the immigration officer told me that i cant do this again but they will let me in this time ... but cz of that paper trouble i finally overstayed and it was a stupid thing to do ... i thought that when we get married it will be ok .. but after we checked they told us that the paper will take about 6 months then we can get married .!! i didnt know what to do i cant oversaty that long so i went to the tokyo immigration and told them my story and that i want to stay and i explained why i cant go back to my country ! they took my pic and finger prints and they told me to go back tomorrow with my gf for an oral hearing and that if i cant stay ill be deported with 5 years penalty ! so i did this last month ! little bit more than a month now ! they called me once asking for 4 5 by 5 cm pic and some other paper after a week from that call they told me to choose between 29 .30 or 31 this mont to go there and i really dont know why .. this is where i need help : can any one tell me why does they need the photos and any idea why did they tell me to choose a date to go back there and for what thanx and sorry for making the story too long